The present invention relates to a glass antenna which is arranged on a glass such as a rear windshield glass with a defogger, a method of setting the glass antenna on the glass, and parts of the glass antenna.
In a glass antenna with a defogger, how to remove the influence of the defogger is a major subject.
For example, in glass antennas disclosed in Japanese Patent Laid-Open No. 61-73403 and Japanese Utility Model Laid-Open No. 4-59606, an antenna wire which has a shape similar to a pole antenna, is electrically insulated from a defogger, and extends in a direction perpendicular to a defogger heating wire, is proposed. However, the performance of the antenna wire arranged in such conventional glass antennas is far from that of a pole antenna although its shape is similar to the pole antenna, since the mechanism of the influence of the defogger on the antenna performance has remained unsolved.
In view of this problem, the inventors of the present application have proposed a glass antenna, which has, in a region where a defogger is extended, a first conductor line which perpendicularly crosses heating wires of the defogger extending in the widthwise direction of a vehicle and are electrically connected thereto in DC term, and a loop-shaped second conductor wire which is connected to none of the heating wires of the defogger, as Japanese Patent Application No. 6-205767 (U.S. application Ser. No. 08/362,788), and the like. In particular, the objective of this glass antenna is to eliminate the influence of the defogger by capacitively coupling a piece of conductor portion, which is closest to the defogger and extends in the widthwise direction of the vehicle, of the second conductor wire at a capacity of about 4 pF or more to the uppermost (or top) heating wire of the defogger extending in the widthwise direction of the vehicle.
However, the glass antenna in the above application can obtain reception characteristics as high as those of the pole antenna, but the antenna conductors must be buried in or deposited on the glass (especially, since the second antenna conductor must be connected to the defogger heating wires in DC term). Accordingly, it is impossible for the end user to set a new glass antenna on the windshield glass of his or her vehicle.